摘要
华北地区是我国空气污染最严重的地区之一.泰山为华北平原最高峰,可代表华北地区背景大气的环境特征.本研究利用2021年6−8月在泰山顶的强化观测数据,开展了基于观测的化学盒子模型模拟,结合位于泰山下国控站点(泰安市监测站)同期监测数据的对比分析,探究了泰山顶夏季PM_(2.5)和O_(3)的污染特征及成因机制.结果表明:①观测期间,泰山顶NO2、SO2、CO的日均浓度均明显低于泰山下,而泰山顶O_(3)浓度相对更高.泰山顶O_(3)浓度超标天数为61 d,超标率为67.0%,最长连续超标天数达23 d;泰山顶PM_(2.5)日均浓度亦略高于泰山下.②泰山顶日间(07:00−17:00)O_(3)浓度主要来源于光化学反应,而夜间主要来源于区域传输.观测期间,泰山顶O_(3)的生成主要处于NO_(x)控制区.③随PM_(2.5)小时平均浓度的增加,其中二次无机盐(硫酸盐、硝酸盐和铵盐)浓度增加的比例大于有机物;与清洁时段(PM_(2.5)小时浓度小于35μg/m^(3)的时段)相比,PM_(2.5)污染时段(PM_(2.5)小时浓度大于35μg/m^(3)的时段)二次无机盐浓度占比增加了13.1%.④泰山顶PM_(2.5)日均浓度和O_(3)日最大8 h平均浓度(MDA8 O_(3)浓度)呈显著正相关(R=0.73,P<0.01).观测期间共发生50次PM_(2.5)和O_(3)小时浓度同步升高的现象,O_(3)浓度平均升速为(10.1±5.3)μg/(m^(3)·h),PM_(2.5)浓度平均升速为(9.5±6.4)μg/(m^(3)·h),二者同步升高的持续时间为2~14 h.PM_(2.5)和O_(3)小时浓度同步升高的过程倾向于发生在静风时段,与地面污染物向山顶输送、光化学反应、液相反应及残留层中的传输过程有关.研究显示,泰山O_(3)和PM_(2.5)污染防控需关注周边地区污染物排放及残留层传输的影响.
North China has been one of the regions with the most serious air pollution in China.As the highest peak in the North China Plain,Mount Tai can represent the environmental characteristics of the background atmosphere in the North China.This study investigated the characteristics of PM_(2.5) and O_(3) pollution at the summit of Mount Tai from June to August 2021.Using observation models,a comprehensive analysis of the mechanism of O_(3) pollution at the summit of Mount Tai was conducted.Meanwhile,a comparative analysis was conducted on the air pollution conditions at the summit of Mount Tai and the Tai′an Monitoring Station at the foot of Mount Tai.The research results show that:(1)The daily average concentrations of NO2,SO2 and CO at the summit of Mount Tai were significantly lower than those at the foot of the Mount Tai,while the O_(3)concentration at the summit was relatively higher.Ozone-pollution days accounted for 67.0%,totaling 61 days,of which the longest O_(3)pollution event lasted for 23 days.The daily average concentration of PM_(2.5)at the summit was slightly higher than that at the foot of the mountain.(2)Ozone concentration during the day(07:00-17:00)was mainly affected by photochemical reactions,and at night it was primarily affected by regional transportations.During the observation period,O_(3) formation at the summit of Mount Tai was more sensitive to NO_(x).(3)As the hourly PM_(2.5) concentration increased,the proportion of secondary inorganic salts(sulfate,nitrate and ammonium salt)in PM_(2.5) increased more than that of organic compounds.Compared with the cleaner periods,the proportion of secondary inorganic salts increased by 13.1%during the pollution period.(4)A significant positive correlation(R=0.73,P<0.01)was observed between the daily average concentration of PM_(2.5)and the 8-hour average daily maximum concentration of ozone(MDA8 O_(3))at the summit of Mount Tai.A total of 50 cases of simultaneous increases in O_(3)and PM_(2.5)hourly concentrations occurred during the observation period.The average increase rate of O_(3)was(10.1±5.3)μg/(m^(3)·h)and the average increase rate was(9.5±6.4)μg/(m^(3)·h)for PM_(2.5).These events typically occurred during calm wind periods,last between 2 and 14 hours,and were associated with the transport of ground air pollutants,photochemical reactions,liquid-phase reactions,and migration processes within the residual layer.The research results show that the prevention and control of O_(3)and PM_(2.5)pollution in Mount Tai needs to focus on the impact of pollutant emissions on surrounding areas and the transmission effect within the residual layer.
作者
乜艳秋
朱玉姣
张吉
赵勇
国兆新
刘玉虹
李洪勇
吴迪
高健
李红
王新锋
薛丽坤
王文兴
NIE Yanqiu;ZHU Yujiao;ZHANG Ji;ZHAO Yong;GUO Zhaoxin;LIU Yuhong;LI Hongyong;WU Di;GAO Jian;LI Hong;WANG Xinfeng;XUE Likun;WANG Wenxing(Environment Research Institute,Shandong University,Qingdao 266237,China;Taishan National Reference Climatological Station,Tai′an 271000,China;State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2024年第3期427-438,共12页
Research of Environmental Sciences
基金
国家自然科学基金项目(No.42075094,42075104)
大气重污染成因与治理攻关项目(No.DQGG2021101)。
